I stayed in Mill Valley, California. In fact I have stayed several times. The law is clear and we verified it with the local police. Parking on the side of the street is legal, but it is necessary to move the vehicle every 30 days to verify is has not been abandoned. At 28 days, the police left a warning on the vehicle advising that it needed to be moved. We left before the 30th day. For other visits, we stayed much shorter time periods.
It makes no difference what the residents of Grants Pass or some place in California want. They cannot prohibit sleeping in a legally parked car or RV. They cannot legally concoct some sort of special rules for residents versus non residents.